1. Technical Field
This invention relates generally to telephones, and, more particularly, optional upgrade circuitry for telephones.
2. Related Art
Conventional telephone model lines typically include a basic telephone which contains the most basic and common features desired and used by the telephone user. In addition to these basic functions, a desk unit may perform additional functions which the customer may need or desire. Examples of such additional functions include adding a speaker, encryption or decryption of the voice message, adding a headset to the telephone, or interfacing the basic telephone to a recording device.
One conventional technique used to add these additional upgrades to a basic telephone has been to replace the basic telephone model with another model having the desired functional configuration. A disadvantage of this technique is that it requires maintaining multiple lines of telephones, each comprising one or more different upgrade functions. Another disadvantage is that this technique requires additional trained service personnel to install the new models at the customer site.
Another conventional technique for providing additional upgrade functions to a basic telephone has been to manufacture the basic telephone model with connectors on one or both of its sides. These connectors interface to a separate module which contains the desired upgrade function. This technique increases the size of the footprint of the phone and makes the basic telephone cosmetically unappealing for those who do not receive such upgrades. In addition, such option modules are sensitive to lateral forces which, if applied while the phone is attached to the basic telephone, can stress or break internal components in either the upgrade module or the basic telephone.
Another conventional technique has been to attach a piece of sheet metal to the bottom of the basic telephone and then attach the option module to this same piece of sheet metal. Electrical connections are then achieved by a cable assembly. The drawback to this technique is the high part and assembly cost due to the large number of additional parts, the bottom surface of the telephone must be dedicated to the attachment of this option module, and the weight of the entire telephone is significantly increased, leading to component failures if the phone is dropped.
What is needed is a telephone option module with upgradable circuitry which can be installed in a basic telephone. The option module needs to be installed in such a manner as to minimize the increase in the footprint of the basic telephone. In addition, the option module needs to be secured to the telephone in such a manner that prevents the option module and basic telephone from being damaged when subjected to significant forces. The option module also must not produce cosmetic difficulties in the basic telephone. There should not be, for example, visible wires connecting the option module and the basic telephone after it is installed, nor should the basic telephone have connectors visible to the user when no option module is installed.